Casting rolls.



J. L. LEWIS. CASTING ROLLS. APPLICATION FILED JAN. 24. 1906.

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Patented Sept. 14, 1909.

2 SHEETS-SHEET 1.

J. L. LEWIS.

CASTING ROLLS. APPLICATION FILED JAN. 24, 1906.

933,996, Patented Sept. 14,1909. 2 sums-suns!- 2. H52. Flllfiwrrussszs:

' To all whom it. may concern:

'UNITED sanrns JOHN L. LEWIS, OI PITTSBUBG, PENNSYLVANIA.

cas'rme ROLLS.

Specification of Letters Patent.

Patented Sept. 1a, 1909.

Application filed January 24, 1906. Serial No. 297,706.

Be it known that I, JOHN L. Lewis, residing. at Pittsburg, in the countyof Allegheny of sand loam having a matrix for the journal at one end ofthe roll, a drag also formed of loam sand and having a matrix for theother roll journal and also having the necessary sprues or passages forthe inflow of molten metal, and one or more chilling cylinders formed ofcast iron and arranged between the cope and drag. These chillingcyllnders which are now made witha uniform thickness of wall areprovided at their ends with radial lugs which are sometimes continuousforming laterally projecting flanges as shown in Figure 2. As these lugsor flangesare employed only for the purpose of connecting the chillingcylinders to the cope and drag and to other chilling cylinders when twoor more such cylinders are employed, they are made of only sufficientthickness to" afiord the desired strength and rigidity for coupling theseveral parts together. The mold constructed as described is arrangedvertically and the molten metal enters through the drag rising upthrough the latter, and the chilling cylinder to the cope. As the moltenmetal comes into contact with the almost cold me tallic surface of thechilling cylinders a thin skin or. shell is formed on and completelyIIVlOSlllg the mass of molten metal which when cold will form the rolland the chill- I ing cylinders become heated and expand proportional tothe degree of heating.

I have found that the chilling cylinders are subjected during thecasting of the roll to some force which causes a peripheral enlargementof the cylinders, the enlargement being greater at the ends. Thisenlargementproduced during casting does not entirely disappear after acasting has been made but the end portions are permanently enlarged. Asthis enlargement occurs after each casting, it results that althougheach increment is small the cylinders Wlll soon assume an hour-glassshape as shown at a in Fig. 1. This expansion of the cylinders seems tobe due'to an irregular heating of the chilling cylinders or to anununiform action of the heat on the cylinder. VVhatever may be the causeof the irregular expansion of the chilling cylinders and the incrementalenlargement of the ends thereof,

the deformation of the cylinders causes a considerable loss in defectivecastings. As

the thin shell formed on the roll surface on contact of the molten metalwith the chilling cylinder condition by the fluid interior of thecasting, it will have but little strength, so that when the ends of thechilling cylinder exand outwardly leaving the thin' skin or shellunsupported laterally or crosswise the pressure of the fluid column willcause a bulging and very frequently a rupture of this shelldiametrically on a plane with the end portions of the cylinder as shownat b in Flg. 1. Where two or more chilling cylinders are employed thedouble bulging diametrically on a plane with the adjacent ends of thechilling cylinders seems to subject the thin shell to such longitudinalstrains that the ruptures are peripheral as shown at c Fig. 1.

' The present invention has for its object an equalization of the rateof expansion ofall parts of the chilling cylinder or cylinders, therebymaintaining a lateral support at all points for the thin shell or skinfirst formed by contact of the molten metal with the chilling cylinders.This equalization may be attained either by retarding the expansion ofthe end portions of the chilling cylinders or accelerating the rate ofexpansion of the waist portion or portions of such cylinders by theapplication of heat thereto. -The .invention is hereinafter more fullydescribed and claimed.

In the accompanying drawings forming a part of this specification Fig. 1is a sectional elevation of the usual form of mold for casting a chilledroll, showing the latter in position in the mold and illustrating theresults of the unequal expansion of the chilling cylinders. Fig. 2 is anenlarged secment, and Fig. 6 isa sectional elevation showing twochilling cylinders of the form shown in Fig. 3 arranged together. forthe production of a long roll.

will be kept in a highly heatedconstructed or by proporti V In thepractice of my invention'I provide" means whereby the expansion of theends of the chilling cylinder may be retarded or that of the waist. ormiddle portions of cylinders 'may be accelerated, such'retardation oracceleration bein so regulated that the rate of expansion sha' be thesame orsubstantially the same at all points of the'cylinders. Theretardation or acceleration may be efiected .in many ways, as bythe-application of a cooling or heating medium to the respective ing thethickportions of the chilling cyzlniuders as new ness of the wall of-the chil ing cylinder at certain points. -This latter method whichmaybe carried out either by reducing the .thickness of the wall at andadjacent to the waist of the'cylinders as shown in Fig. 2, or byincreasing the thickness of the end .portions of the cylinders, is formany reasons preferred, and of these two alternative steps theincreasing of the end portions of the cylinders is pre rred.

As shown in Fi s. 3, 4, 5, and 6, the; required thickness 0 wall at theends of the chilling cylinders can be attained by increasing thethickness and radial extension of the flanges 2 at the ends of thechilling cylinders. The amount of metal thus added at the ends'andadjacent portions of the cylinders is such that by the time the heatfrom the molten metal has diffused equally through the end portions, thewaist portion will have been raised to the same'temperature,and theexpansion due to such heating will. be the same at all points, and the.relative internal dimensions will be preserved which is-the purpose ofthe invention. As shownin Figs. Sand 6 the added metal may project withconsiderable abruptness from;

' the body ofthe cylinder or may extendwith a more or less radualdecrease in thickness toward the waist of cylinder as shown in Figs. 4and 5. In the construction shown-in Figs.- 3, 4, and 5 the added metalwhich is largely in excess of that required for chilling purposes isdisposed in massive flange form and clamps can be readily appliedthereto, as is the present practice, for connecting the chillingcylinder to the cope and draw and another cylinder when twoor more arereing chilled rol iguired. When the metal addedas to form a wallgradually decreasing in thick ness towardthe waist, fnotches 3 areprovided for the reception of the-fiends of the clamps, j As shew inFig. 2 the cylinders now in use can be so altered as y decreasing thethickness of the wall of the waist portion as to--insure a practicallyequal-rate of expansion of all portions of the cylinder.- Theretardation of the expansion of theends of the cylinderscan be effectedby applying a cooling fluid to such portions, and

an acceleration of the expansion of the waist of the cylinder can be.had by applying a heating medium as gas jets to such waist portion.

Practical use of 'my'inve ntion hasshown that by properly proportioningthe thickness of the metal at the ends and waist porvtions of thechilling cylinder or cylinders the rates of expansion .-will bepracticalsl the same at all points and the chilling cy 'nder orcylinders will retain their cylindrical shape and hence there willnot beany bulg-- in or swelling'out of-any portion of the rofi formed in suchmold. j

' While "I have described with considerable particularity forms ofapparatus forcarry-- mg out my improved method, no claim is made hereinto such apparatus as the same forms the subject matter of applicationfiled June 16th, 1906, Set. lid-391,976. I claimherein as myinvention: 1. As an improvement in the art of casting chilled rolls, themethod herein described which consists in preventing an irregular Intestimony whereof, I havejhereuntoset my hand. j

JOHN L. LEWIS. Witnesses:

CHARLES BARNETT, Morrow JoHNs'roN.

